Swing Trade Position Size Calculator

How the FullStack Alpha swing trade planner works

Most swing accounts do not blow up on one bad pick. They blow up on size. This planner turns the amount you are willing to lose into an exact share count before you click buy.

What it calculates

You enter five numbers: account size, risk per trade as a percent, entry price, stop-loss and target price. The planner returns the whole number of shares to buy, the dollars at risk, the total position size, the risk/reward ratio, and your profit or loss if the target or the stop gets hit.

Everything runs in your browser. No signup, no account, nothing stored.

The math behind it

• Dollar risk = account size × risk percent
• Risk per share = entry price minus stop-loss
• Shares to buy = dollar risk ÷ risk per share, rounded down to a whole share
• Risk/reward = (target minus entry) ÷ (entry minus stop)

A worked example

Say you have a $25,000 account and risk 1% per trade. That is $250. You want to buy at $50 with a stop at $47, so each share risks $3. The planner tells you to buy 83 shares, a $4,150 position. With a target of $56, each share can make $6 against $3 of risk, a 1:2 risk/reward. Hit the target and you make about $498. Hit the stop and you lose about $249, right at your plan.

Where traders get this wrong

They set the stop where the loss feels small instead of where the setup is proven wrong. A stop tucked inside a stock's normal daily range gets tagged by noise. Put the stop where the idea fails, then let the planner shrink the share count to fit your risk. Wider stop, fewer shares, same dollar risk.

The planner flags any trade below a 1:2 risk/reward. Below that line, a 50% win rate barely covers costs. Tighten the entry or raise the target before you take it.

Who it is for

Swing traders who hold stocks and ETFs for days to weeks and want every position sized by rule, not by feel. Pair it with the FullStack Alpha expectancy calculator to check whether your win rate and payoff actually add up to an edge.